【摘要】 利用祁连山海北高寒草甸地区 2 0 0 0年植物生长期内的太阳辐射观测资料 ,分析了该地区太阳紫外辐射 (UV)在植物生长期内的日、季节变化特征 ,以及在太阳总辐射 (Eg)中所占的比例 (η)。结果表明 :海北站地区UV较强 ,瞬时极大值可达 77W·m-2 ,日总量最大达 1.8MJ·m-2 以上 ;实际天气状况下月总量最大可达 4 1.6 2 0MJ·m-2 (5月 ) ,植物生长期内的 4月到 10月总量达 2 18.6 5 1MJ·m-2 。UV有明显的日、季节变化规律。日间UV所表现的单峰式曲线变化过程 ,与总辐射变化有关。在晴天状况下 ,η的变化下午高于上午 ,日平均约为 0 .0 4 8;阴天状况下在 13:0 0～ 14 :0 0较高 ,早晚低 ,且随云层厚薄而发生显著的变化。同时表明 ,阴天状况下的η值 (0 .0 5 3)高于晴天。就生长期实际情况来看 ,η值在植物生长的前期较高 ,植物生长后期较低 ,植物生长期内平均约为 0 .0 5 2。受强UV的影响 ,高寒草甸几种主要植物 ,其植物根、茎、叶的可溶性糖含量、淀粉含量、非结构性碳水化合物均较高 ,且表现出日出后迅速增加 ,植物根茎粗壮等 ,植物的生理适应性及其植物体的结构发生改变 ,致使高寒草甸植物具有明显的抗寒性功能机制和形态结构。更多还原

【Abstract】 The diurnal and seasonal varying characteristics of solar ultraviolet radiation and the ratio(η) of UV to total radiationduring the plant growing season were analysed by observed radiation data in the area of Haibei alpine meadow of Qilian mountain in 2000. Ultraviolet radiation was higher in this area. The instant maximum ultraviolet radiation was 77 W·m -2 ,thetotal maximum ultraviolet radiation in a day was more than 1.8 MJ·m -2 , the accumulated ultraviolet radiation in a month was 41.620 MJ·m -2 (May) under the real weather condition; the total accumulated ultraviolet radiation was 218.651MJ·m -2 during the plant growing season(from April to October). The ultraviolet radiation had obvious diurnal and seasonal changing pattern in this area. The diurnal variation of ultraviolet radiation showed as a single peak curve which was related with the total radiation change caused by the change of sun’s altitude. The change of η in a sunny day was higher in the morning, lower in the afternoon, average value was 0.048; whereas the change of η in a cloudy day was higher from 13:00 to 14:00, lower in the morning and night, and changed obviously with the change of cloudy amount. The η in a overcast day was higher than that in a sunny day. η was higher in the prior plant growing period, lower in later plant growing period and the average η was about 0.052. Owing to the strong UV effect, the soluble sugar, starch and non\|structural carbon\|hydrate component quantity of root, stem and leaf of several main plants were higher and showed as the rapidly increase after the sun rise; plant root, stem and other organs were thicker and stronger. The plant physiology adaption and its structure chinging made the alpine meadow plants had obvious functional mechanism and morphological structure against cold conditions in alpine meadow under the influence of stronger ultraviolet radiation.更多还原